On her last day of work, homicide detective Sarah Linden is drawn into a new case about the disappearance of a teenage girl, Rosie Larsen. Mitch and Stan Larsen frantically try to track down their daughter when they learn she did not show up at school. City Councilman Darren Richmond prepares for an important forum with the Mayor as the election nears.
The investigation into Rosie’s killer begins as Sarah and Holder question the missing girl’s parents, Stan and Mitch, as well as Rosie’s friends and City Councilman Richmond. Rosie’s school becomes a potential murder site when Sarah and Holder uncover shocking evidence on campus. Heartbroken and grief-stricken, Mitch and Stan face the aftermath of losing their daughter.
City Councilman Richmond suspects a leak within his own team, causing a shakeup in his campaign. Sarah and Holder track down a potential witness to the murder and are led to a new suspect. Mitch shuts down completely, forcing Stan to take on both parenting roles as his family grapples with the reality of losing Rosie.
Sarah and Holder pressure Rosie’s former boyfriend, Jasper, for answers and interview a new suspect. An emotionally vulnerable Stan and Mitch plan their daughter’s funeral. Rosie’s best friend, Sterling, reveals some surprising truths about Rosie’s life. With a campaign that is struggling financially, Richmond attends a posh party in the hopes of raising funds.
Rosie's teacher provides Sarah and Holder with a new piece of evidence. Richmond's campaign team plans a new anti-crime television commercial. Mitch continues to struggle with the loss of her daughter, while Stan becomes more determined to find Rosie's killer, and asks his colleague Belko for help.
Sarah and Holder question a suspect's family and neighbors. Tension mounts between Richmond and his campaign advisor, Gwen, as his team prepares for an important debate with the Mayor. Rosie's funeral takes place. Stan takes matters into his own hands.
The police learn more about Rosie's whereabouts on the night of her death; Richmond deals with a negative ad; Mitch starts doubting the police investigation.
Sarah and Holder evade the FBI and unearth new evidence. Mitch endangers the boys, prompting Stan to take matters into his own hands. Richmond tries to climb back into the race.
The police are stymied while trying to make an arrest. Richmond contemplates dropping out of the race. Fed up with the police, the Larsens take action.
The cops regroup. Richmond goes up in the polls. Stan faces consequences for his actions.
Sarah and Holder discover more on Rosie, but the investigation gets stalled when they have to set out on a search for Jack.
The police connect Rosie to a suspicious website. Stan faces his demons while Mitch learns secrets she never knew about Rosie.
The police connect a new piece of evidence to Rosie the night of her murder. Stan and Mitch reflect on the past as the future of their family hangs in the balance.
In the aftermath of the shooting at City Hall and Linden's discovery that the photo leading to Councilman Darren Richmond's arrest was forged, Sarah returns to Seattle to investigate a possible cover up and wonders if she can trust her partner.
An ominous discovery is made at the Larsen house while Sarah travels to Tacoma to learn Councilman Richmond's dark secret. Meanwhile, Richmond is forced to come to grips with the fallout from the attack at City Hall.
Holder falls from grace while Sarah tracks down Rosie's backpack. Richmond confronts the truth about his situation and Stan gets in deeper with the mob while Mitch resurfaces.
Sarah and Holder identify the mystery man with the tattoo while Jamie attempts to enlist Gwen's help and Stan learns his past may have come back to haunt him.
Sarah gets a mysterious message from Rosie Larsen that may identify the killer while Mitch befriends a runaway girl and Richmond questions his political future.
Sarah focuses in on a Larsen family secret, Stan faces his past sins, Mitch shelters a runaway girl, and Richmond has a surprise visitor.
The investigation returns to the casino. Tension erupts at the Larsen house. Stan meets Richmond face to face for the first time to make an uneasy alliance.
When Holder goes missing, Linden is desperate to find him. Stan takes matters into his own hands. Richmond returns to City Hall.
Richmond attempts to help the investigation. Sarah tracks down Rosie's key. Stan realizes his son is in trouble. Mitch reaches her destination.
Sarah teeters on the edge. Stan attempts to make amends. Richmond receives an unexpected boost in the mayoral race.
After returning to the casino, Sarah and Holder find themselves on the run. Stan and Richmond must make life-altering decisions that will decide their fates.
Linden and Holder have the killer within reach. The Richmond campaign prepares for Election Day. The Larsen family attempts to regain a sense of normalcy.
Sarah and Holder close the case. Richmond sets out on a bold new path. The Larsen family gains closure from an unsuspected source.